Automatic adjustment of circuit breakers



7 Aug. 1, 1933.

M. MORRISON AUTOMATIC ADJUSTMENT 0F CIRCUIT BREAKERS Filed Dec. 31, 1930 2 Sheets-Sheet l T/z0 6222b Man/7mm Mom/50 Aug. 1, 1933. o so 1,920,656

AUTOMATIC ADJUSTMENT 0F CIRCUIT BREAKERS Filed Dec. 31, 1930 2 Sheets-Sheet 2 Patented Aug. 1, 1933 UNITED STATES 'AUTOMATIC ADJUSTMENT OF BREAKERS CIRCUIT Montford Morrison, Montclair, N. J., assignor to v Westinghouse X-Ray Company, Inc., a Corporation of Delaware Application December 31, 1930. Serial No. 505,789 r 4 Claims. (01. 250-s4) 'My invention relates to X-ray apparatus and has particular relation to an X-ray circuit in which the X-ray tube is protected by a circuit breaker interposed in the supply circuit. i

More particularly stated my invention has reference to a method of regulating the circuit breaker in accordance with the current supplied to an X-ray tube, in such a manner that the greater the amount of current flowing through the tube, the greater the rapidity with which the circuit breaker will open the circuit, when some abnormal condition takes place in the circuit.

In X-ray circuits some type of safety device is usually employed to protect the X-ray tube against damage but these devices have heretofore been responsive to a fixed amount of current which when exceeded opens the circuit. Other typesof safety devices, such as circuit breakers, although adjustable are responsive tov the particular setting to which the device is adjusted and it occasionally happens that great damage is done to the X-ray tube and apparatus before the circuit is opened under abnormal conditions.

It is accordingly an object of my invention to provide in an X-ray circuit a circuit breaker which is automatically adjusted.

Another object of my invention is the provision of a device associated with a circuitbreaker which automatically adjusts the breaker in accordance with the current flowing in an X-ray tube circuit.

A further object of my invention is the provision of a device associated with a circuit breaker interposedin an X-ray system which increases the rapidityof operation of the circuit breaker in response to the occurrence of abnormal conditions, in the system, and simultaneously increases the current in the system.

Still further objects of my invention will become apparent to those skilled in the art by reference to the accompanying drawings wherein:

Figure 1 is a diagrammatical view of an X-ray circuit in which one form of my invention is utilized; and I l Figure 2 is a diagrammatical view of an X-ray circuit showing the utilization of a modification of myinvention.

Referring now to the drawings in detail I'have shown in Fig. 1 an auto-transformer 2 arranged to be energized from a suitable source. of commercial potentiaLsuch as an alternating current generator 3, through suitable conductors L1 and L2. A suitable switch 4 is provided in the conductor L2 for the purpose of opening and closing the supply circuit to. the auto-transformer 2. Aconductor 5 extends from one end of the Wind ductors 23 and 24 to the filament of an X-ray ing of the auto-transformer to one end of a primary winding 6 of a high-tension transformer '7, while another conductor 8 extends from an adjustable arm of the auto-transformer through a. coil 9, of a circuit breaker 10, to a contact terminal 12. A conductor 13 extends fromanother contact terminal 14 to the other end of the primary winding sand the circuit breaker 10 is provided with a contact member 15, which when the breaker is operated tothe closed position, completes'the circuit to the primary winding '6. A low tension transformer 16 isarranged "to have its primary winding 17 receive energization from a suitable source such asthe generator 3. A supply conductor L3 extends from the generator 3 to one end of the primary winding 1'7 while a conductor L4 extends from the generator, through a suitable switch 18, to a movable contact arm 19 of a rheostat 20. A conductor 21 then extends from the windings of the rheostat 20 to the other end of the primary winding 17 for completing the circuit. The movable contact arm 19 of the rheostat 20 is associated with the circuit breaker 10 so as to adjust the breaker in accordance with movements of the rheostat when the latter is op-' erated to vary the current supplied to the primary winding 17, as more fully hereinafter. explained.

The secondary. winding 22 of the low tension transformer 16 is connectedby meansof conconductor 23. It. thus becomes readily apparent that Whentheprimary windings 6 and 17 are energized thefilament of the X-ray tube 25 is heated by means of the secondarywinding 22 and that energy will flow between the electrodes of the tube from the secondary winding 26 of the hightension transformer 7.

Referring now to the adjustment of the circuit breaker in accordance with the current flowing, in the X-ray tube I have shown in this modification a base 32 which is provided with a pair of bearing brackets 33 in which a shaft 34 is journaled.

The contact arm 19 of the rheostat 20 is secured to one'end of this shaft 34 and a control knob 35 is secured to the other end of this shaft for operating the contact arm 19. A cam surfaced roller 36, having a notched portion 37, is rigidly secured to this shaft 34 with its periphery in contact with a plunger 38 which passes through the coil 9 of the circuit breaker l0.

Rotation of the control knob 35 moves the contact arm 19 to vary the current supplied to the transformer .16 and also rotates the cam surfaced roller 36. Rotation of this latter roller, raises or lowers the plunger 38 depending upon the direction of rotation of the knob 35. The raising or lowering of this plunger 38 thus changes the 10 length of travel of the plunger necessary to open the circuit breaker 10 in response to abnormal conditions which would cause. excessivecurrent to flow through the coil 9.

The operation of this embodiment of my ini5 vention is as follows: the switch 18 is first closed to energize the transformer '16 for heating the filament of the X-ray tube. The control knob is then rotated in a counter-clockwise direction;

as viewed from Fig. l, and moves the contact arm.

: 19 over the windings of the rheostat 20 to increase the current 'to the desired amount. The switch 4 isthen closed to energize the auto-transformer 2 and the circuit breaker 10 is, closed to thus energize the high'tension transformer 7 and the X-ray sa- 'tube 25.. r r

The rotation of thecontrol. knob 35 in a counterclockwise direction also rotates the cam surfaced roller 36,;which due to its configuration,

limits the downward movement of the plunger 38.

As the circuit breaker 10 is opened by an upward movementof the plunger 38, in response to excessive currents flowing through the winding of the coil'9,- the limiting of the downward movement or open the-breakerupon any abnormal conditions occurring in the circuit. It 1 consequently follows that thegreater the amount of current flowingin the circuit the greater will bethe rapidity 4 with which the breaker will trip under all abnormal conditions.

Rotation of the knob and arm 19 in a clock- Wise direction reduces the amount of current flowing in the circuit by excluding the windings 5d; of the rheostat 20 from thecircuit and at .the-

same time rotates the cam roller 36 to allow further downward movement. of the plunger 38. When the windings of the rheostat 20 are entirely excluded from the circuit,,or in other words 55 when the arm 19 is moved in a clockwise direce tionto its limit of travel, the cam roller 36 is rotated until the plunger 38 no longer contacts the roller 36 but drops" into the notched portion 37;. In this position the plunger is in its extreme Qcdownwardposition which requires the greatest length of travel before tripping the breaker l0 and opening the circuit.

It is to be noted, however that with the plunger in this latter position and even-though the minimum amount of current is flowing through the Xu'aytube 25, the breaker is su'ifi ciently calibrated to allow opening of the circuit upon occurrence of all abnormal conditions with- I out damage resulting to the circuit or to the Q Xeray tube. r

.R eferring-now' to the modification shown in Fig. .2 pI-have shown in addition to the circuit breaker- 10, another circuit breaker 42 interposed in. the conductor 5, and providedwitha coil 43 in serieswiththe primary winding .6 and of the circuit breaker '10 The core is pivpurpose of the adjustable spring is to adjust the auto-transformer 2, in the same manner is the coil 9 of the circuit breaker 10. The conductor L3 connecting the source of energy 3 with latter members as in'the modification previously described.

The conductor L4 connecting the other side of the source 3 with the primary winding 17 has a coilr44"surrounding a inagnetic core 45 and con nected in series with this latter coil 44 is another coil. 46 which surrounds the elongated core 38 otallysecured to a double faced rotatable cam 4! each face of which is rovided with a lateral projection 48 and 49=respectively. An adjustable coil spring 50 is secured to one of these pro-' jections 49 and to fixed point of the apparatus for tensioning the cam 4'1.

The other extension 48 of. the cam 4'? contacts a core or plunger 52 of the circuit breaker 42 which is surrounded by the winding 43.. The I the circuit breakers 10. and 42 in order to preset these breakers for opening when current flowingthrough the system exceeds a predetermined. amount. 1

The windings 44 and 46 areoppositely poled so that the current flowing through the 'coil 44 draws the core 45 downwardly while the current flowing through coil, 46 moves the .core 38 upwardly. As the, current flowing from the source 3 to the primary winding 1'7 is increased by the rheostat-EG it naturally follows that the current flowing in the coils 44 and 46 is'likewise increased thus moving the respective cores 45 and 38 still further in the directions just mentioned. The upward, movement of the core 38, being in the direction, necessary to open the breaker l0, renders the remaining distance of travel totrip. the breaker considerably less which allows azrapid opening of the breaker. by excessive currents due to abnormal condition flowing through the coils 9 or 46. a a The downward movement of the corei45 rotates the cam 47 which due to the. contact of the lateral projections 48 with the core 52 raises this latter core in the same mannerv as the core 38.- By increasing the tension of thecoil spring 50 the current flowing through .the coil 44 is thus limited by the choking effect ofthis coil andthe current "flowing through the coil.'46 is likewise limiteddue'to the series connection of 139 these two coils 44 and 46. In consequence' oi this limiting of the current inthe coils 44 and 46, the cores 38, 45and 52 are also limited in their movement in response to the current fiowing'in the circuit, as the current is varied by the regulationof the rheostat 20. f .5 i It is obvious from the foregoing that the oper.-: ation of this modification of my invention'is identical tothe operation of the embodiment previously described difiering only in the mechanical 149 structure in the one instance associated withthe rheostat and the circuit breaker, andiin the latter modification the association of the plurality of circuit breakers with the circuit and responsive to the currentflowing therethrough, as regulated by therheostat, is entirely electrical.

Itcan, therefore, be readily seen that I have provided a circuit breaker that may be employed in an X-ray tube circuit, which is automatically adjustedin accordance with the current flowing in the circuit and in which the rapidity of operation increases with an increase of current in the circuit. Although I have shown and described several embodiments of my invention I do not desire to be limited thereto as various other modifications of the same may be made without departing from the spirit and scope of the appended claims.

What is claimed is: V 1. In an X-ray system, an X-ray tube, a big tension transformer for energizing said X-ray tube, a source of energy for said hightension transformer, a circuit breaker interposed between said source and said high tension transformer responsive to the occurrence of abnormal conditions in said system for disconnecting said high tension transformer from said source, a low tension transformer for supplying heating currents to said X-ray tube, a rheostat connected to said 10w tension transformer for varying the current supplied to said X-ray tube, and electrical means associated with said circuit breaker and in series with said rheostat for adjusting said circuit breaker in response to operation of said rheostat. 2. In an X-ray system, an X-ray tube, a high tension transformer for energizing said Xray tube, a source of energy for said high tension transformer, a circuit breaker interposed between said source and said high tension transformer tension transformer for energizing said X-ray tube, a source of energy for said high tension transformer, a circuit 1 breaker interposed between said source and' said high tension transformer responsive to the occurrence of abnormal conditions in said system for disconnecting said high tensiontransformer from said source, a low tension transformer for supplying heating currents to said X-ray tube, a rheostat connected to said low tension transformer for varying the current supplied to said X-ray tube and means electrically responsive to the variations of current supplied to said X-ray tube by operation of said rheostat and. associated with said circuit breaker for changing the rapidity of operation of said circuit breaker in response to the occurrence of abnormal conditions in said system simultaneously with the operation of said rheostat.

4. In an X-ray system, an X-ray tube, a high tension transformer for'energizing said tube, a source of energy for said high tension transformer, a circuit breaker interposed between said source and said high tension transformer responsive to the occurrence of abnormal conditions in said system for disconnecting said high tension transformer from said source, a low tension transformer for supplying heating currents to said X-ray tube, said circuit breaker provided with a plurality of windings, one ofsaid windings being connected in series with said source and said high tension transformer, and the other of said windings being connected in series with said source and said low tension transformer and. a rheostat connected in series with said last men'- tioned winding and transformer for varying the current supplied to said X-ray tube whereby an increase of current supplied to said X-ray tube by operation of said rheostat simultaneously increases the rapidity of operation of said circuit breaker in response to the occurrence of abnormal conditions in said system. I

, MONTFORD MORRISON. 

